Manhole lifts are eye bolt-like devices 10 illustrated in FIGS. 5 and 6 that are positioned within a lift insert 12 imbedded in concrete 50 that forms a manhole or other precast concrete product. Manhole lift 10 permits the attachment of chains and other devices to lift a pre-cast concrete product in order to transport it and ultimately position it where it is to be used.
Lift inserts 12 have a bayonet-type socket, and lifts 10 have bayonet-type bases formed by two opposed ears 16 on the lift shaft 18 that are received in opposed grooves 20 in insert 12. After lift 10 is fully inserted in insert 12, it is rotated one quarter turn, as shown in FIG. 6, to lock it in place so that it will not withdraw from insert 12.
Prior devices for holding insert 12 in position within a manhole or other pre-cast concrete product form have utilized expensive, relatively complex devices with a spring loaded shaft having a bayonet base that locks within the bayonet socket in an insert 12 in the same manner as a manhole lift 10 locks in insert 12. The expense, complexity and other problems associated with such devices make it desirable to have a simpler, easier to use device for holding a lift insert 12 in position during the concrete casting process.